Between cochlear implants and quadri/paraplegics, there are approximately 700,000 persons in the U.S. who would benefit from prosthetics utilizing neural or neuromuscular stimulation. Such systems require implantable, high-speed, bi-directional, transcutaneous data transmission immune to variations in the local environment. To date, data links in development are not projected to meet the combined needs of speed and integrity. This proposal describes a proof-of-concept Phase I for an optical data link with transmission capability in the megabit per second range. The Phase I program will incorporate a prototype data link system into an of-the-shelf transcutaneous energy transmission system and verify its performance. The design is flexible in nature to allow simple incorporation into a variety of prosthetic devices. Phase II would complete such an incorporation, miniaturize, and do in vivo testing.